1. Field of the Invention
The present invention relates to the stator of the high-pressure turbine in a turbine engine. It particularly relates to the sections of the stator that are opposite the rotor blades on the first stage of the high-pressure turbine.
2. Description of the Related Art
Referring to FIG. 1, in a number of examples of turbine engines the turbine casing 1 of the stator comprises annular sections 2 that are positioned opposite blades 3 of rotor 4 at the entrance to the high-pressure turbine downstream of combustion chamber 5. Therefore, these annular sections 2 of the turbine casing 1 create play with the top of blades 3 of stator thereby determining the efficiency of the turbine engine.
However, these annular sections 2 are supplied with gas at temperatures that enable them either to dilate or to contract in order to reduce the play that exists between these blades 3 and these annular sections 2 to an absolute minimum and thereby increase the efficiency of the turbine engine. The gas is generally drawn from another area of the turbine engine according to the temperature of the gas or the speed of the rotor.
Referring to FIG. 2, the annular section of the stator comprises an inner ring that can be in a single piece but that often comprises a series of ring sections 6 that face the end of blades 3 of the rotor. They are supported by a spacer section 10 that is fastened to the turbine casing 1 and in which at least one cavity 11 is provided and that is in contact with ring sections 6 in order for thermal adjustment to be made to said ring sections. These ring sections 6 are fastened to spacer sections 10 of the stator using grips 7 that are positioned on the respective downstream flanges 8 and 9 of ring sections 6 and spacer sections 10, these two flanges 8 and 9 abutting. The upstream fastening is achieved by an upstream flange 12 of each spacer section 10 being inserted into an upstream groove 13 of each ring section 6.
It should be noted that this type of high-pressure turbine engine can comprise several stages of this kind and several subsequent ring section and spacer section stages. The ring sections 6 are located at the entrance to the high-pressure turbine in a zone where the temperature can reach 1,500.degree. C. Consequently, the ring sections must be cooled. Also, the leaktightness between these ring sections 6 and spacer sections 10 must be as tight as possible in order to avoid any loss of the air flow from the turbine engine. The fastening grips 7 partly enable this leaktightness to be achieved. However, given the dilation due to differences in temperatures during operation, air leaks occur and the amount of air flow required from the engine to cool ring sections 6 can be significant.
The aim of the invention is to overcome this drawback by minimizing the leaks and the air flow taken from the engine in order to maintain a high level of efficiency from the turbine engine.